Method of assembling skylight structures

ABSTRACT

A skylight structure having a condensate removal system is constructed by lowering the purlins directly down onto upwardly facing portions of the rafters without having to spread the rafters to admit projecting end portions of the rafters. Also, the rafters and purlins may be joined with vertical and horizontally extending pins providing a hidden interconnection between the rafters and purlins rather than joining the purlins and rafters by exposed brackets and bolts. In the preferred skylight structure, the purlins and rafters are formed of closed tubular members having hidden condensate removal channels on the upper portions thereof with the condensate channels in the purlins extending into curbs resting in notches in the rafters and discharging condensate into underlying condensate collecting channels in the rafters.

United States Patent t191 nu 3,844,086

Radtke [45] Oct. 29, 1974 [54] METHOD OF ASSEMBLING SKYLIGHT Primary Examiner-John E. Murtagh STRUCTURES Carl Radtke, Chicago, Ill.

Assignee: Paper Corporation, Kankakee, Ill.

Filed: Aug. 14, 1972 Appl. No.: 280,435

Inventor:

U.S. Cl 52/741, 52/474, 52/464, 52/669, 52/395 Int. Cl. A01g 9/14, EOb 3/54, E04 3/28 Field of Search 52/208, 209, 475-477, 52/459, 464, 741, 395, 669

References Cited UNITED STATES PATENTS Lietaert 52/209 Assistant Examiner-James L. Ridgiu, Jr. Attorney, Agent, or Firm-Fitch, Even, Tabin & Luedeka [57] ABSTRACT A skylight structure having a condensate removal system is constructed by lowering the purlins directly down onto upwardly facing portionsof the rafters without having to spread the rafters to admit projecting end portions of the rafters. Also, the rafters and purlins may be joined with vertical and horizontally extending pins providing a hidden interconnection between the rafters and purlins rather than joining the purlins and rafters by exposed brackets and bolts. ln the preferred skylight structure, the purlins and rafters are formed of closed tubular members having hidden condensate removal channels on the upper portions thereof with the condensate channels in the purlins ex- 5 tending into curbs resting in notches in the rafters and discharging condensate into underlying condensate collecting channels in the rafters.

5 Claims, 7 Drawing Figures This invention relates to a skylight structure having purlins and rafters joined into a framework supporting glazing panels of uninsulated glass, plastic, acrylic or the like.

Skylight structures of this general kind are assembled on site or adjacent the location of ultimate use such as in a shopping center, a building, a library, a swimming pool, etc. Such skylight structures are large and cover substantially surface areas with a series of purlins spanning each of a plurality of rows of rafters to form the grid or skeleton framework for supporting the marginal edges of the glazing panels laid upon the assembled grid. In some instances, the skylight structure is assembled on the ground or an adjacent roof and lifted into place by a crane. In other instances, the skylight structure is assembled in situ. In any event, rafters are first positioned and then the individual purlins are fastened to the supporting rafters by various brackets, e.g., angIe-shaped brackets having the portions bolted to the respective rafters and purlins.

In many of these skylight structures, the ends of the purlins are formed with projections to fit into a central recess in the rafters and the end projections on the purlins are fastened to the central portions of the rafters. However, the total length of the purlin from one end projection to other end projection is greater than open span between the longitudinal top edges of the rafters thereby preventing the purlins from being lowered or dropped directly into position for bolting to the rafters. Particularly, when a series of purlins span each row of rafters, the rafters must be spread, that is, pivoted about one end to provide a sufficient opening therebetween to allow the ends of the purlins to be projected into the central portions of the rafters.

The spreading of the rafters to allow insertion of the projecting ends of the purlins into the rafter recesses is time consuming and hence costly. This` is particularly true, if it necessitates, as in some cases, the erection of scaffolding beneath the purlins to support them while the rafters are being spread and returned prior to fastening the purlins to the rafters.

Additionally, as disclosed more fully in co-pending application entitled "Skylight Structure and Structural Members Therefor" of Hans F. Schultz and Carl Radtke, Ser. No. 265,164, filed June 22, 1972 the brackets, bolts and nut fasteners are aesthetically displeasing for some structures and hence are desired to be eliminated. Also, as explained in that co-pending application, a cleaner appearance may be achieved with closed tubular purlins and rafter structural members having a hidden condensate system in contrast to the prior art visible condensate channel flanges and exposed purlin receiving recesses in the rafters.

Accordingly, a general object of the present invention is to provide a new and improved method of assembling a skylight structure.

Another object is to provide a method of assembling a skylight structure having closed tubular purlins joined to closed tubular rafters.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings in which:

FIG. 1 is a fragmentary, diagrammatic elevational view of a skylight structure constructed in accordance with the method of the present invention;

FIG. 2 is a diagrammatic exploded view showing a preferred construction of purlins and rafters joined together with the method of the present invention;

FIG. 3 is a perspective view partially in section showing the rafters and purlins of FIG. 2 joined together;

FIG. 4 is a diagrammatic view showing the lowering of the purlins illustrated in FIGS. 1 and 2 into position on the rafters in accordance with the present invention.

FIG. 5 is a view showing the preferred manner of interlocking the purlin and rafters without the use of nuts and bolts;

FIG. 6 illustrates a double glazed structure assembled in accordance with the method of the present invention; and

FIG. 7 is a partially exploded view showing the double glazed structure of FIG. 6.

As shown in the drawings for purposes of illustration, the invention is embodied, very generally, in a skylight structure 1l, which may take various shapes other than the rectangular, planar configuration shown in FIG. l, for installation in buildings or structures 13 in which a roof or portion of the roof is formed by the skylight structure. Typically, the skylight structure comprises an array of glazing panels 12 usually of a transparent, tinted or transluscent glass or of a plastic such as arcylic plastic mounted in a supporting grid or framework 14 comprised of rows of rafters l5 spanned by purlins 17. More specifically, the glazing panels l2 are supported along a first pair of marginal edges thereof by the usually vertically extending rafters l5 and along a second pair of marginal edges by the crosswise extending purlins 17.

In accordance with the present invention, the skylight structure 11 may be assembled in situ or in adjacent area for lifting into place by a crane without having to spread the rafters 15 to allow the lowering of series of purlins l7 into position, as is illustrated in FIG. 4, there being four such purlins 17 between each pair of adjacent rafters l5 in the skylight structure illustrated herein. More specifically, the method of fabrication of the skylight structure 1l generally comprises the steps of: assembling a plurality of rafters in predetermined and fixed positions relative to one another at which positions the rafters will remain during the further assembly of the skylight structure, lowering the purlins directly down onto the positioned rafters at predetermined longitudinally spaced positions along each row of rafters to span adjacent pairs of the rafters, resting curbs 22 projecting from each end of the purlins onto upwardly facing portions of the rafters, interlocking each of the purlins with its supporting rafters with condensate channels 23 of the purlins being superposed with condensate channels 24 in the rafters to deliver condensate thereto, and securing glazing panels 12 to the purlin abd rafter gridwork 14. Also, in accordance with another aspect of invention, the fastening of the purlins to the rafters may include the further step of positioning and driving of pin means 25 between portions of the purlins and portions of the rafters to interconnect the rafters and purlins. This latter manner of fastening eliminates the need for fixing angle brackets with nuts and bolts between the purlins and rafters as in the prior art methods. As will be explained in greater detail hereinafter, the invention may be used with various other forms of purlins 17 and rafters l5 including, for example, non-tubular shaped purlins and rafters as will be described.

Referring now in greater detail to the rafters and purlins 17 illustrated in FIGS. 25, the purlins 17 are closed tubular members formed of a lightweight metal such as aluminum by an extrusion process with four side walls 26 joined together to enclose a hollow interior 27 for each purlin 17 and a hollow interior 28 for each rafter l5. The extrusions are made in relatively long lengths and are severed and cut the desired length for a purlin or rafter. The curbs 22 are formed by saw cutting portions of purlins 17 to leave the illustrated projecting ends which will rest on a rafter surface 37 located, in this instance, in a notch 29 cut in the rafter. As best seen in FIG. 2, the curb 22 projects outwardly from a vertical end wall 3l for the purlin which, when assembled to a rafter 15, abuts a vertical sidewall 33 of the rafter. The curb 22 includes the top one of the four walls 26 of the purlin along with a short portion of the depending side walls 26.

The purlins 17 are formed so that the distance between their respective end walls 31 thereof is substantially identical to the distance between walls 33 of a pair of adjacent rafters 15. As the distance between ends 39 of the curbs 22 is greater than the distance between walls 33 of the adjacent pairs of rafters, the curbs 22 may project over and rest on the surfaces 37 of the rafters.

Recapitulating, and with reference to FIG. 4, with the rafters 15 positioned in place at a fixed distance A therebetween which is equal to the distance between end walls 3l of a purlin 17, the purlins 17 may be dropped straight downwardly with the walls 31 of the purlins traveling downwardly along the pair of facing vertical rafter walls 33 until an underside 41 of the curb 22 abuts the horizontal supporting surfaces 37 in the notches 29 in the rafters. In this manner, the purlins 17 may be lowered into position without having to spread the rafters, that is, to pivot the end of one of the pair of rafters to accommodate the purlins as with prior art skylight structures.

Also, in accordance with another aspect of the invention, the purlins 17 may be fastened and interconnected to the rafters 15 with hidden pin means 25 rather than the exposed nuts, bolts and angle brackets as is common in prior art methods of construction. For this purpose, the purlins 17 carry a pair of downwardly projecting roll pins 45 which have lower free ends projecting beneath the curb 22 for insertion into the rafter condensate channels 24, as best seen in FIG. 5, when the curb 22 rests on the surfaces 37 of the rafters 1.5. As best seen in FIG. 5, the lower ends of the roll pins 45 extend downwardly along and will abut an upstanding rafter channel wall 49 should the purlin 17 tend to move laterally and try to separate from the rafter. Preferably, the roll pins 45 are split longitudinally and experience a slight compression and decrease in diameter when driven into vertically extending holes 5l in a thickened portion 53 in the top wall 26 ofthe purlin 17. The pins 4S are thus flexed, i.e., tensioned. into engagement with the walls ofthe holes 5l and are thereby held against dropping through the holes 5l. While the pins are preferably inserted into the holes 5l prior to placing the purlin 17 into position on the rafters 15, the pins 45 may be driven into the holes 51 after the purlin is lowered onto the supporting rafters.

Although the purlins 17 are generally located at the desired spacings along the rafters 15 when their curbs 22 are inserted into the notches 29 in the rafter and their movement longitudinally of the rafter is generally limited by vertical sidewalls 55 of the notches, the pin means 25 more precisely locates and holds the purlins against shifting on the rafters and from lifting therefrom due to uplift forces caused by a wind. To this end, the pin means 25 further comprises pins 57 which extend generally horizontally between the rafters and purlins with one end of each pin positioned in a channel 59 in the purlin and an opposite end within an aperture 6l in the rafter 15. The horizontally disposed pins 57 are also split longitudinally to have a tight fit at its receiving aperture 6l. Whereas the vertically disposed pins 45 are preferably located in apertures 51 prior to lowering the purlin 17 onto the rafter, the horizontally extending pins 57 are installed after the purlins are placed on the rafters. The pins 57 are placed adjacent the bottom of and at opposite ends of the channels 59 in the purlin 17 and then moved along the channel 59 and inserted at one end thereof into an aperture 6l. The pins 57 are usually tapped into the apertures 61 which may be drilled into the rafters either at the site of erection or prior to shipping to the erecting site.

With the purlin curbs 22 positioned on the rafters 15,

condensate collected in the purlin condensate channels 23 will flow and drop into the underlying rafter condensate channels 24 along paths designated by the directional arrows shown in FIG. 5. The curb end 39 extends adjacent to but is spaced from an upstanding wall 69 on the rafter 15 to allow the water to flow across the end of the purlin curb and to drop through the space and into the underlying rafter condensate channel 24. This space is assured by dimensioning the distance between the curb end 39 and the vertical end wall 3l of the purlin 17 to be less than the distance between the exterior surface of the rafter sidewall 33 and the upstanding glazing channel wall 69.

With the framework 14 assembled, the glazing panels 12 may then be placed on the framework and secured in place. The glazing panels 12 are lowered onto longitudinally extending glazing strips 73 (FIG. 3) carried by the purlins 17 and the longitudinally extending glazing strips 75 carried by the rafters l5, the glazing strips 73 and 75 being in a common plane. That is, a pair of marginal edges 77 for each of the glazing panels 12 rest on the purlin glazing strips 73 and the other pair of marginal edges 79 for each of the glazing panels l2 rest on the glazing strips 75.

Preferably, each of the glazing strips 73 and 75 are formed of an elastomeric resilient material such as neoprene to resiliently support the glazing panels. As best seen in FIG. 5, the preferred glazing strips 73 and 75 have lower dovetailed portions fitted into dovetailed shaped grooves in similarly shaped channels on the top walls of the purlins and rafters. The upper edges of the glazing strips are sawtoothed and flattened slightly by exterior clamping bars or caps to provide moistureproof and airproof seals with the marginal edges of the glazing panels 12.

The end edges of the glazing panels 12 may be cushioned, particularly on the downhill side of the glazing panels 12 by glazing blocks 8l and 82 carried in channels 84 formed in the top walls in the rafters l5 and purlins 17. The glazing blocks 81 and 82 are formed of resilient material such as neoprene. The channels 84 in the purlins also serve to collect any moisture by passing the glazing strips and to deliver this moisture to the condensate channels 24 in the rafters 15. ln the rafters 1'5, the channels 84 also serve to collect bypass water, but they deliver the water to the lower ends of the rafters for collection in a suitable gutter or discharge system (not shown).

After positioning the glazing panels 12 on the respective glazing strips 73 and 75, the glazing panels may be secured to the purlin and rafter framework 14 by means of glazing caps 85 and 86 which are clamped against the outer marginal edges of the glazing panels 12 by suitable screw fasteners 89. In this instance, the screw fasteners 89 are in the form of self-tapping screws having an exterior head and a shank with a screw thread 91 which is centered between and screwed into the pair of upstanding channel defining walls 93 integral with the top walls for the purlins and rafters. The walls 93 define therebetween the channel 59 into which the roll pins 57 were inserted. On the underside of the glazing caps are formed depending, longitudinally extending flanges 94 which straddle the upstanding screw receiving walls 93 of the purlins and rafters to center the caps on the purlins and rafters. This aligns the resilient glazing strips 9S on the undersides of glazing caps over the glazing strips 73 and 75 supporting the marginal edges of the glazing panels 12. By tightening the self-tapping screws 89, the glazing caps 85 and 86 apply clamping forces through their glazing strips to panels 12 and also serve to clamp the purlins 17, the latter being held against lifting from the notches 29 in the rafters l5 by the pins 57.

Thus, it will be seen that skylight structure has been assembled without the use of a scaffolding under the purlins or a spreading of the rafters to admit the purlins,

ln accordance with the invention, a double glazed structure 100, as best seen in FIGS. 6 and 7, may be assembled with the method steps of: assembling a plurality of rafters 101 in predetermined and fixed positions relative to one another at which positions the rafters will remain during further assembly of the skylight structure, lowering purlins 103 directly down onto the positioned rafters at predetermined and longitudinally spaced positions along each row of rafters to span adjacent pairs of the rafters, resting curbs 105 projecting from each end of the purlins onto upwardly facing portions of the rafters, interlocking each of the purlins to its supporting rafters to form a framework lll with condensate channels 107 of the purlins being superposed with condensate channels 109 in the rafters to deliver condensate thereto, and securing a first set of glazing panels 115 to the framework 111 and securing a second set of glazing panels 113 to the framework 111.

Referring now in greater detail to the illustrated elements of double glazed skylight structure 100, the lower set of glazing panels 113 are secured to lower sections 116 of generally l-shaped purlins 103 and rafters 101 while separated via air space 117 from the upper set of glazing panels 11S carried by upper sections 118 of the rafters 101 and purlins 103.

The rafters 101 and purlins 103 are formed of aluminum extrusions which are generally severed to size. The upper ends of the purlins 103 are each cut to leave projecting curbs projecting outwardly from an end 119 of a central web 121 extending between the upper and lower sections of the purlin. The curb 105 also projects outwardly of an end wall 123 for the lower sections of the purlin. When the lower end 123 of the purlin abuts a longitudinally extending side wall 125 of the rafter, the curb 105 will extend over and be resting on an upper edge 129 of an upstanding wall 131 forming the other side of the condensate channel 109 for the rafter 101. ln this instance, the purlin supporting surface 129 is sufficiently beneath the plane of glazing panel supporting strips 133 on the rafter 101, as best seen in FlG. 6, that there is no need to cut a notch similar to the notch 29 used in the above-described ernbodiment of the invention as illustrated in F lGS. 1-5 to receive the curb.

The preferred manner of interconnecting the purlins 103 to the rafters 101 is by a hidden pin means 137 which includes a pair of downwardly extending pins 139 and a horizontally extending pin 141 at each end of the purlin 103. More specifically, the pins 139 are fastened at upper ends within vertically extending holes 143 drilled within the top wall of the purlin leaving the lower free ends thereof projecting downwardly and into the rafter condensate channels 109. The pins 139 will abut the upstanding condensate channel walls 131 on the rafters should the purlins move laterally outwardly from their supporting purlins.

To assure the flow of condensate from the purlin condensate channels 107 into rafter condensate channels 109, the ends 147 of the curbs 105 are spaced from an upstanding wall 149 on the rafter 101 to allow condensate to drop in the manner described above in connection with FIGS. 1-5. ln this instance, the rafter 101 is provided with two condensate channels 109 whereas the purlins 103 are provided with only one condensate channel 107.

Each of the purlins 103 and rafters 101 has an upper and lower pair of glazing strips 150 formed of neoprene to support the marginal edges of the respective glazing panels 113 and 115 in the manner hereinbefore described. Likewise, glazing blocks 152 may be provided in channels formed in the respective rafters and purlins to cushion the marginal edges of the glazing panels abutting these glazing blocks.

Preferably, the upper set of glazing panels 115 are secured to the purlin and rafter framework 111 as by clamping with glazing caps 155 similar to the glazing caps 85 and 86 previously described. However, the lower set of glazing panels 113 are clamped by brackets 157 to the lower rafter and purlin sections 116 and on their supporting glazing strips 150 by means of clamping brackets 157. The latter have a downwardly facing glazing strip 159 for alignment with and for clamping the marginal edges of the glazing panels 113 to the underlying glazing strips 150 on lower sections of the purlins and rafters. The clamping brackets 157 also include a central web 161 which extends to an upstanding flange 163 fastened by nuts and bolts 165 to the upstanding webs for the respective purlins and rafters.

ln assembly of the double glazed structure, the lower glazing panels 113 are secured to the framework 111 prior to placing the upper panels 115 into position and securing them in place with the glazing caps 155. Thus, the double glazed skylight structure may be assembled without spreading the rafters or using an underlying scaffolding to support the purlins during spreading of the rafters. a

From the foregoing, it will be seen that the present invention provides a method of constructing skylights with lowering purlins directly into supporting positions on the rafters without having to spread the rafters or to provide an underlying scaffolding to support the purlins while the rafters are being spread. Also, in accordance withthe preferred embodiment of the invention, the rafters and purlins are interconnected with hidden pins rather than the use of angle brackets and nuts and bolts as in the prior arts. Also, in the illustrated constructions, the curbs on the purlins have condensate channels therein to deliver condensate to underlying condensate channels in the rafters in a hidden condensate system.

While a preferred embodiment has been shown and described, it will be understood that there is no intent to limit the invention by such disclosure but, rather, it is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. A method of assembling a skylight structure having purlins with integral condensate channels thereon joined to rafters having integral condensate channels thereon, said rafter having notches therein in a framework supporting glazing panels and providing a condensate removal system, said purlins having projecting ends thereon, said method comprising the steps of: assembling a plurality of rafters in predetermined and fixed positions relative to one another with said notches facing upwardly and at distances to be spanned within said projecting ends at which positions the rafters will remain during and after light structure, lowering the purlins directly down onto upwardly facing notches of said rafters at predetermined longitudinally spaced positions along each pair of adjacent rafters to span the same with glazing supporting portions of said purlins facing upwardly, resting curbs projecting from each end of the purlins onto upwardly facing notches of the rafters with said upwardly facing glazing supporting portions aligned to support a glazing panel and simultaneously forming said condensate drainage system with the ends said integral condensate channels in said purlins being superimposed over the integral condensate channels in said rafters to form said condensate removal system without adding additional separate condensate gutters therebetween, interlocking each of the purlins to its supporting rafters with condensate channels in the purlins extending into said projections and superposed over condensate channels in the rafters for discharging condensate to the latter` lowering glazing panels onto said upwardly facing portions of said rafters and purlins, and securing glazing panels in said purlin and rafter framework to fabricate said skylight structure having a condensate removal system.

2. A method of assembling a skylight structure having closed tubular purlins with integral condensate channels on the upper portions thereof joined to rafters with integral condensate channels on the upper portions thereof and having notches therein in a framework supporting glazing panels and providing a condensate removal system, said purlins having projecting end portions thereon, said method comprising the steps of: as-

further assembling ofthe skysembling at least three rafters in predetermined and fixed parallel positions relative to one another each with said notches facing upwardly and at distances to be spanned by said projecting ends with inner ones of said rafters having pairs of opposed pairs of notches for supporting ends of pairs of purlins adjacent each other and at which positions the rafters will remain during and after further assembling of the skylight structure, lowering onto a first pair of said rafters a series of purlins spaced longitudinally of the rafters without spreading the first rafter pair with the projecting end portions of each of the purlins of the series directly down into said upwardly facing notches of said rafters at prede termined longitudinally spaced positions along said first pair of rafters to span the same with glazing supporting portions of said purlins facing upwardly, resting said end portions projecting from each end of the purlins onto upwardly facing notches of the rafters with said upwardly facing glazing supporting portions aligned to support a glazing panel and simultaneously superimposing the integral condensate channels in said end portions of said purlins over the integral condensate channels in said rafters without spreading said rafters thereby forming said condensate removal system, without spreading an adjacent third rafter and without spreading an adjacent rafter which was one of said first pair of rafters lowering a series of purlins into the notches of this common center rafter and said third rafter with saidv purlins in each series being aligned, interlocking each of the purlins to its supporting rafters with condensate channels in the purlins extending into said ends thereof and superposed over condensate channels in the rafters for discharging condensate to the latter by pins extending horizontally and vertically between the ends of the purlins and into portions of the rafters to interlock the purlins and rafters with hidden pins, lowering glazing panels onto said upwardly facing portions of said rafters and purlins, and securing glazing panels in said purlin and rafter framework to fabricate said skylight structure having a condensate removal system.

3. A method in accordance with claim 2 in which the step of securing said glazing panels to said framework comprises laying a lower set of glazing panels in position on said framework and securing them to said framework and laying an upper set of glazing panels at positions on said framework spaced above said lower glazing panels and securing said upper glazing panels to said framework.

4. A method in accordance with claim 2 in which the step of resting the purlin curbs on the rafters comprises the further steps of: depositing the purlin curbs on a vertically extending outer wall of a condensate channel and spacing the terminal portions of said condensate channel in said curbs from said rafters and over said rafter condensate channels to allow the condensate to flow from the terminal ends of the purlin condensate channels and to drop into the underlying condensate channels.

5. A method in accordance with claim 4 in which said interlocking of said purlins and rafters comprises the steps of inserting depending pins on said curbs into said rafter condensate channels and inserting an horizontally extending pin between adjacent portions of said purlins and said rafters.

* l lt tk lf UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,844,086 Dated October 29, 1974 Inventor(s) Car]- Radtke It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Cover page, change the nameA of the Assignee from "Paper Corporation" to --Roper Corporation.

signed and sealed this 29th day of Aprill 19,75.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissloner of Patents Attestng Officer and Trademarks FORM PO-1050 (10.69) 

1. A method of assembling a skylight structure having purlins with integral condensate channels thereon joined to rafters having integral condensate channels thereon, said rafter having notches therein in a framework supporting glazing panels and providing a condensate removal system, said purlins having projecting ends thereon, said method comprising the steps of: assembling a plurality of rafters in predetermined and fixed positions relative to one another with said notches facing upwardly and at distances to be spanned within said projecting ends at which positions the rafters will remain during and after further assembling of the skylight strUcture, lowering the purlins directly down onto upwardly facing notches of said rafters at predetermined longitudinally spaced positions along each pair of adjacent rafters to span the same with glazing supporting portions of said purlins facing upwardly, resting curbs projecting from each end of the purlins onto upwardly facing notches of the rafters with said upwardly facing glazing supporting portions aligned to support a glazing panel and simultaneously forming said condensate drainage system with the ends said integral condensate channels in said purlins being superimposed over the integral condensate channels in said rafters to form said condensate removal system without adding additional separate condensate gutters therebetween, interlocking each of the purlins to its supporting rafters with condensate channels in the purlins extending into said projections and superposed over condensate channels in the rafters for discharging condensate to the latter, lowering glazing panels onto said upwardly facing portions of said rafters and purlins, and securing glazing panels in said purlin and rafter framework to fabricate said skylight structure having a condensate removal system.
 2. A method of assembling a skylight structure having closed tubular purlins with integral condensate channels on the upper portions thereof joined to rafters with integral condensate channels on the upper portions thereof and having notches therein in a framework supporting glazing panels and providing a condensate removal system, said purlins having projecting end portions thereon, said method comprising the steps of: assembling at least three rafters in predetermined and fixed parallel positions relative to one another each with said notches facing upwardly and at distances to be spanned by said projecting ends with inner ones of said rafters having pairs of opposed pairs of notches for supporting ends of pairs of purlins adjacent each other and at which positions the rafters will remain during and after further assembling of the skylight structure, lowering onto a first pair of said rafters a series of purlins spaced longitudinally of the rafters without spreading the first rafter pair with the projecting end portions of each of the purlins of the series directly down into said upwardly facing notches of said rafters at predetermined longitudinally spaced positions along said first pair of rafters to span the same with glazing supporting portions of said purlins facing upwardly, resting said end portions projecting from each end of the purlins onto upwardly facing notches of the rafters with said upwardly facing glazing supporting portions aligned to support a glazing panel and simultaneously superimposing the integral condensate channels in said end portions of said purlins over the integral condensate channels in said rafters without spreading said rafters thereby forming said condensate removal system, without spreading an adjacent third rafter and without spreading an adjacent rafter which was one of said first pair of rafters lowering a series of purlins into the notches of this common center rafter and said third rafter with said purlins in each series being aligned, interlocking each of the purlins to its supporting rafters with condensate channels in the purlins extending into said ends thereof and superposed over condensate channels in the rafters for discharging condensate to the latter by pins extending horizontally and vertically between the ends of the purlins and into portions of the rafters to interlock the purlins and rafters with hidden pins, lowering glazing panels onto said upwardly facing portions of said rafters and purlins, and securing glazing panels in said purlin and rafter framework to fabricate said skylight structure having a condensate removal system.
 3. A method in accordance with claim 2 in which the step of securing said glazing panels to said framework comprises laying a lower set of glazing panels in position on said framework and securing them to said fraMework and laying an upper set of glazing panels at positions on said framework spaced above said lower glazing panels and securing said upper glazing panels to said framework.
 4. A method in accordance with claim 2 in which the step of resting the purlin curbs on the rafters comprises the further steps of: depositing the purlin curbs on a vertically extending outer wall of a condensate channel and spacing the terminal portions of said condensate channel in said curbs from said rafters and over said rafter condensate channels to allow the condensate to flow from the terminal ends of the purlin condensate channels and to drop into the underlying condensate channels.
 5. A method in accordance with claim 4 in which said interlocking of said purlins and rafters comprises the steps of inserting depending pins on said curbs into said rafter condensate channels and inserting an horizontally extending pin between adjacent portions of said purlins and said rafters. 